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Diffstat (limited to 'intern/cycles/render/gpu_display.h')
| -rw-r--r-- | intern/cycles/render/gpu_display.h | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/intern/cycles/render/gpu_display.h b/intern/cycles/render/gpu_display.h new file mode 100644 index 00000000000..a01348d28d5 --- /dev/null +++ b/intern/cycles/render/gpu_display.h @@ -0,0 +1,247 @@ +/* + * Copyright 2021 Blender Foundation + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#pragma once + +#include "device/device_graphics_interop.h" +#include "util/util_half.h" +#include "util/util_thread.h" +#include "util/util_types.h" + +CCL_NAMESPACE_BEGIN + +class BufferParams; + +/* GPUDisplay class takes care of drawing render result in a viewport. The render result is stored + * in a GPU-side texture, which is updated from a path tracer and drawn by an application. + * + * The base GPUDisplay does some special texture state tracking, which allows render Session to + * make decisions on whether reset for an updated state is possible or not. This state should only + * be tracked in a base class and a particular implementation should not worry about it. + * + * The subclasses should only implement the pure virtual methods, which allows them to not worry + * about parent method calls, which helps them to be as small and reliable as possible. */ + +class GPUDisplayParams { + public: + /* Offset of the display within a viewport. + * For example, set to a lower-bottom corner of border render in Blender's viewport. */ + int2 offset = make_int2(0, 0); + + /* Full viewport size. + * + * NOTE: Is not affected by the resolution divider. */ + int2 full_size = make_int2(0, 0); + + /* Effective vieport size. + * In the case of border render, size of the border rectangle. + * + * NOTE: Is not affected by the resolution divider. */ + int2 size = make_int2(0, 0); + + bool modified(const GPUDisplayParams &other) const + { + return !(offset == other.offset && full_size == other.full_size && size == other.size); + } +}; + +class GPUDisplay { + public: + GPUDisplay() = default; + virtual ~GPUDisplay() = default; + + /* Reset the display for the new state of render session. Is called whenever session is reset, + * which happens on changes like viewport navigation or viewport dimension change. + * + * This call will configure parameters for a changed buffer and reset the texture state. */ + void reset(const BufferParams &buffer_params); + + const GPUDisplayParams &get_params() const + { + return params_; + } + + /* -------------------------------------------------------------------- + * Update procedure. + * + * These calls indicates a desire of the caller to update content of the displayed texture. */ + + /* Returns true when update is ready. Update should be finished with update_end(). + * + * If false is returned then no update is possible, and no update_end() call is needed. + * + * The texture width and height denotes an actual resolution of the underlying render result. */ + bool update_begin(int texture_width, int texture_height); + + void update_end(); + + /* Get currently configured texture size of the display (as configured by `update_begin()`. */ + int2 get_texture_size() const; + + /* -------------------------------------------------------------------- + * Texture update from CPU buffer. + * + * NOTE: The GPUDisplay should be marked for an update being in process with `update_begin()`. + * + * Most portable implementation, which must be supported by all platforms. Might not be the most + * efficient one. + */ + + /* Copy buffer of rendered pixels of a given size into a given position of the texture. + * + * This function does not acquire a lock. The reason for this is is to allow use of this function + * for partial updates from different devices. In this case the caller will acquire the lock + * once, update all the slices and release + * the lock once. This will ensure that draw() will never use partially updated texture. */ + void copy_pixels_to_texture( + const half4 *rgba_pixels, int texture_x, int texture_y, int pixels_width, int pixels_height); + + /* -------------------------------------------------------------------- + * Texture buffer mapping. + * + * This functionality is used to update GPU-side texture content without need to maintain CPU + * side buffer on the caller. + * + * NOTE: The GPUDisplay should be marked for an update being in process with `update_begin()`. + * + * NOTE: Texture buffer can not be mapped while graphics interoperability is active. This means + * that `map_texture_buffer()` is not allowed between `graphics_interop_begin()` and + * `graphics_interop_end()` calls. + */ + + /* Map pixels memory form texture to a buffer available for write from CPU. Width and height will + * define a requested size of the texture to write to. + * Upon success a non-null pointer is returned and the texture buffer is to be unmapped. + * If an error happens during mapping, or if mapping is not supported by this GPU display a + * null pointer is returned and the buffer is NOT to be unmapped. + * + * NOTE: Usually the implementation will rely on a GPU context of some sort, and the GPU context + * is often can not be bound to two threads simultaneously, and can not be released from a + * different thread. This means that the mapping API should be used from the single thread only, + */ + half4 *map_texture_buffer(); + void unmap_texture_buffer(); + + /* -------------------------------------------------------------------- + * Graphics interoperability. + * + * A special code path which allows to update texture content directly from the GPU compute + * device. Complementary part of DeviceGraphicsInterop. + * + * NOTE: Graphics interoperability can not be used while the texture buffer is mapped. This means + * that `graphics_interop_get()` is not allowed between `map_texture_buffer()` and + * `unmap_texture_buffer()` calls. */ + + /* Get GPUDisplay graphics interoperability information which acts as a destination for the + * device API. */ + DeviceGraphicsInteropDestination graphics_interop_get(); + + /* (De)activate GPU display for graphics interoperability outside of regular display update + * routines. */ + virtual void graphics_interop_activate(); + virtual void graphics_interop_deactivate(); + + /* -------------------------------------------------------------------- + * Drawing. + */ + + /* Clear the texture by filling it with all zeroes. + * + * This call might happen in parallel with draw, but can never happen in parallel with the + * update. + * + * The actual zero-ing can be deferred to a later moment. What is important is that after clear + * and before pixels update the drawing texture will be fully empty, and that partial update + * after clear will write new pixel values for an updating area, leaving everything else zeroed. + * + * If the GPU display supports graphics interoperability then the zeroing the display is to be + * delegated to the device via the `DeviceGraphicsInteropDestination`. */ + virtual void clear() = 0; + + /* Draw the current state of the texture. + * + * Returns true if this call did draw an updated state of the texture. */ + bool draw(); + + protected: + /* Implementation-specific calls which subclasses are to implement. + * These `do_foo()` method corresponds to their `foo()` calls, but they are purely virtual to + * simplify their particular implementation. */ + virtual bool do_update_begin(const GPUDisplayParams ¶ms, + int texture_width, + int texture_height) = 0; + virtual void do_update_end() = 0; + + virtual void do_copy_pixels_to_texture(const half4 *rgba_pixels, + int texture_x, + int texture_y, + int pixels_width, + int pixels_height) = 0; + + virtual half4 *do_map_texture_buffer() = 0; + virtual void do_unmap_texture_buffer() = 0; + + /* Note that this might be called in parallel to do_update_begin() and do_update_end(), + * the subclass is responsible for appropriate mutex locks to avoid multiple threads + * editing and drawing the texture at the same time. */ + virtual void do_draw(const GPUDisplayParams ¶ms) = 0; + + virtual DeviceGraphicsInteropDestination do_graphics_interop_get() = 0; + + private: + thread_mutex mutex_; + GPUDisplayParams params_; + + /* Mark texture as its content has been updated. + * Used from places which knows that the texture content has been brought up-to-date, so that the + * drawing knows whether it can be performed, and whether drawing happened with an up-to-date + * texture state. */ + void mark_texture_updated(); + + /* State of the update process. */ + struct { + /* True when update is in process, indicated by `update_begin()` / `update_end()`. */ + bool is_active = false; + } update_state_; + + /* State of the texture, which is needed for an integration with render session and interactive + * updates and navigation. */ + struct { + /* Denotes whether possibly existing state of GPU side texture is still usable. + * It will not be usable in cases like render border did change (in this case we don't want + * previous texture to be rendered at all). + * + * However, if only navigation or object in scene did change, then the outdated state of the + * texture is still usable for draw, preventing display viewport flickering on navigation and + * object modifications. */ + bool is_usable = false; + + /* Texture is considered outdated after `reset()` until the next call of + * `copy_pixels_to_texture()`. */ + bool is_outdated = true; + + /* Texture size in pixels. */ + int2 size = make_int2(0, 0); + } texture_state_; + + /* State of the texture buffer. Is tracked to perform sanity checks. */ + struct { + /* True when the texture buffer is mapped with `map_texture_buffer()`. */ + bool is_mapped = false; + } texture_buffer_state_; +}; + +CCL_NAMESPACE_END |